Alkylated phenols find many uses in industry. They are valuable starting materials for making many antioxidants. In some areas ortho-alkylphenols are the desired isomer. In other areas, para-alkylphenols or mixtures of para- and meta-alkylphenols are more desirable. For example, mixtures of meta- and para-alkylphenols can be reacted with phosphorus oxychloride to form triaryl phosphates which are useful gasoline additives.
Ortho-alkylphenols can be made following the process described in U.S. Pat. No. 2,831,898. When making other alkyl phenol isomers, phenol is usually alkylated using an acidic catalyst which forms mixtures of ortho-, meta- and para-alkylphenols. A useful process for making mixtures of isopropyl phenols which are high in para-isopropylphenols is described in U.S. Pat. No. 4,391,998. According to that patent, a mixture of phenol and either isopropanol or propylene is contacted with a crystalline zeolite catalyst to form a mixture of ortho-, meta- and para-isopropylphenol having an increased para-isopropylphenol content but still containing substantial amounts of ortho-alkylphenol.